Abstract: In order to screen the optimal application amount of nitrogen fertilizer for cauliflower, by taking the cauliflower variety Taiya as the test material, and in accordance with the "Guiding Opinions on Fertilization of Main Crops in Xiamen", on the basis of the same reasonable dosage of phosphorus and potassium fertilizers, no fertilization (CK), no nitrogen fertilization (N₀PK), nitrogen fertilization of 150 kg·hm^-2 (N₁PK), nitrogen fertilization of 300 kg·hm^-2 (N₂PK ) and nitrogen fertilization of 450 kg·hm^-2 (N₃PK) were set respectively, and the field experiments were conducted to study the effects of the rates of nitrogen fertilization on the agronomic traits, yield and economic benefits of cauliflower. The results showed that on the basis of the fertilization of P₂O₅ 120 kg·hm^-2 and K₂O 270 kg·hm^-2, increasing the nitrogen fertilization could improve the main agronomic characters of cauliflower, promote the growth and development of cauliflower, and increase the final yield of cauliflower. Among them, the rate of nitrogen fertilization of 300 kg·hm^-2 significantly increased the yield and efficiency of cauliflower, and the biological yield, commodity output and net income increased by 100.25%, 136.22% and 73,060 yuan·hm^-2, respectively, compared with the treatment without nitrogen fertilization, with the differences being extremely significant.